1. Field of the Invention
The present invention is related to a method for producing metal with a sponge like structure of which density of the pores is controllable. And especially is related to a method derived from the producing method of the U.S. patent application Ser. No. 09/129,985 now U.S. Pat. No. 6,162,310, of the same inventor as the present patent application. The method can control the sizes, shapes and density of mutually communicating pores and communicating areas between every two pores distributed in the metal with the sponge like structure, in this way, physical and mechanical feature of the sponge like structure of the metal can be improved.
2. Description of the Prior Art
In the recent years, porous metal material has been found capability in improving specific weight, pressure resisting strength, toughness etc., and it has a single or compound features of fire-proof capability, sound insulation, heat insulation and magnetic wave disturbance-proofing etc. Thus techniques of development of porous metal material have been noticed by the related arts. In the markets, the already developed porous metals are divided into two classes depending on whether their pores are communicated mutually, i.e., the foamed metals and the air-venting metals.
In which, the pores in the foamed metals are independent without communication, and the foamed metals normally are applied on light weighted constructional material (noise absorber, anti-vibration material, collision buffering material, heat insulating constructional material). And as to the method of manufacturing of such material, the producing method of the U.S. patent application Ser. No. 09/129,985, now U.S. Pat. No. 6,162,310, of the same inventor as the present patent application is preferred. The prior method can effectively control shapes, sizes, volume and density of individual pores of foamed metal, and thus physical and mechanical feature of the sponge like foamed metal material can be improved.
However, the type of metallic tissue of the air-venting metal is provided with a lot of pores communicating with one another, it is more suitable for manufacturing filters, catalysts, sound mufflers, material for electrodes of batteries on heat exchangers, liquid separators, liquid flow adjusters, oxygen processors for purifying water, self-lubricating bearings, LSI heat emitting anti-vibration plate material, wall plates for ships/aircraft/spacecrafts, fillers for plywood etc. The methods for manufacturing it are only the conventional powder metallurgy, foundry of disappearing die, metallic fiber sintering process, foaming method of foam agent etc. A manufacturing technique with high cost of production might be used to make air-venting metal with irregular pore organization of which the pores can be communicated with one another, but it is lack of capability of controlling size, shape and density of tissue. Hence, the physical and mechanical features of the air-venting metal can not be improved, this limits improving of a single or the combined effects of fire-proofing, sound insulation, heat insulation or magnetic wave disturbance-proofing etc.
The object of the present invention is to improve the manufacturing technique in producing sponge like metal having independent air holes as stated in the U.S. patent application Ser. No. 09/129,985, now U.S. Pat. No. 6,162,310 and to develop another technique in easy producing sponge like air-venting metal with a lot of pores communicating with one another and of which the pores are effectively controllable in shape, size and density of tissue. Thereby, the sponge like metal with a lot of pores can be strengthened in its single or the combined effects of fire-proofing, sound insulation, heat insulation or magnetic wave disturbance-proofing etc.
To obtain the above stated object, the present invention has the following steps of selecting organic blanks, medium dipping, accumulation, baking, dipping with mortar in vacuum, drying, immersion, sintering, preheating and vacuum founding etc.
Wherein, when in selecting blanks, in principle, selection of blanks must be done among organic matters (it has less problem of environmental conservation), the shapes and sizes of the blanks are exactly the factors to decide the shapes and volume of the unit hollow pores in the porous sponge like structure; while the arranged form and degree of communication of the porous sponge like structure are controlled by an agglomeration mode in the stop of accumulation.
In the steps of accumulation, in order to effectively control the arrangement and degree of communication of the pores in the porous sponge like structure, the blanks possible of any of various sizes must be dipped with a layer of organic medium which stuck together by adherence, and are formed a shaped embryo after baking, the shaped embryo then is processed in the subsequent procedure.
While in selecting metallic melt and refractory mortar, suitable refractory mortar is selected in pursuance of the fact whether the porous sponge like metal to be made is of an alloy of high melting point or alloy of low melting point. It is attached by dipping on the exterior surface of the shaped embryo. After baking of the refractory mortar, a mixture formulated from water glass, an alloy of high melting point or alloy of low melting point shall be applied by dipping on the refractory mortar layer, for the purpose of increasing adherence between the refractory mortar and the selected metallic melt in the subsequent processing procedure. And the sponge like metal having pores communicating with one another and with desired tissue can be formed by vacuum founding after disappearing of the organic material and the blank by burning.
The present invention will be apparent after reading the detailed description of the preferred embodiments thereof in reference to the accompanying drawings.